Why we don’t know exactly what happened during a near-collision in space

Space traffic experts tracked two pieces of orbital garbage that appeared to be careening toward each other on Thursday night: a defunct Soviet satellite and a discarded Chinese rocket booster. Ultimately, the two objects narrowly missed each other, according to private space-tracking company LeoLabs.



a close up of a computer: Two pieces of orbital space debris appeared to be careening toward each other on Thursday, October 15. Ultimately, the two objects narrowly missed each other, according to a private space-tracking company, LeoLabs.


© Courtesy LeoLabs
Two pieces of orbital space debris appeared to be careening toward each other on Thursday, October 15. Ultimately, the two objects narrowly missed each other, according to a private space-tracking company, LeoLabs.

LeoLabs, which uses its own ground-based radars to track spaceborne objects, put the odds of collision at 10% or greater. That’s high, but not uncommon, LeoLabs CEO Daniel Ceperley told CNN Business on Thursday.

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But the US military, which uses data from the world’s largest network of radars and telescopes, said that its space traffic control team detected a “nearly zero percent probability of collision.”

In response, LeoLabs’s Ceperley said in a statement Friday morning: “We obviously have a great deal of respect for the [US military’s] 18th Space Control Squadron and their estimates. Nobody is disputing that these objects came close to one another.”

Meanwhile, Moriba Jah, an astrodynamicist at the University of Texas at Austin who has long been trying to raise public awareness about the abundance of junk in Earth’s orbit at constant risk of colliding, said the ordeal was only the latest piece of evidence that the world needs an internationally collaborative effort to track space traffic.

His data, an amalgamation of all publicly available real-time space traffic information, show dozens of potential collisions happening at any given moment. Jah suggested the Soviet satellite and discarded rocket booster were expected to come within 72 meters of each other. However, he couldn’t say for sure whether a collision was even “likely.”

Objects in space are tracked with telescopes and radar operated by governments and private companies. But all those organizations around the globe are hesitant to share their data with each other. So, when there is a chance that two things in space might collide, experts have an extremely difficult time hashing out exactly how high the risks are. LeoLabs does not share its data publicly.

Ceperley told CNN Business Thursday that the company decided to raise public awareness about this particular event because the two objects are both large, and because they’re in an area of orbit that’s still relatively clean compared to nearby orbits. The company is also trying to raise more general awareness about the debris problem, he said, to encourage the private sector to develop means of cleaning it up.

“Multiple times a week we’re seeing dead satellites come within 100 meters of each other, moving at tremendous speeds,” Ceperley said.

What happened Thursday

The Soviet satellite, which launched to space in 1989 and was used for navigation, weighs nearly 2,000 pounds and is 55 feet long, according to Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics. The rocket booster, part of a Chinese Long March launch vehicle that likely